Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Long Term Evolution (LTE) wireless networks were standardized by the 3GPP working groups (WG). Orthogonal Frequency Division Multiple Access (OFDMA) and single carrier Frequency Division Multiple Access (SC-FDMA) access schemes were chosen for the down-link (DL) and up-link (UL) of E-UTRAN, respectively. User Equipments (UE's) are time and frequency multiplexed on a physical uplink shared channel (PUSCH) and a physical uplink control channel (PUCCH), and time and frequency synchronization between UE's guarantees optimal intra-cell orthogonality. An important UL reference signal, the Sounding Reference Signal (SRS) is defined in support of frequency dependent scheduling, link adaptation, power control and UL synchronization maintenance, which are functions handled above the Physical Layer, mainly at layer 2. Indeed, the main purpose of this signal is to allow the Base Station, also referred to as eNodeB, estimating a UE's radio channel information on time and frequency resources possibly different from those where it is scheduled. SRS processing occurs at the Physical Layer though and delivers to upper layers mainly three metrics estimated from the SRS:                Channel estimates and gains across the system bandwidth;        Noise variance; and        Timing offset.SRS processing may compute and deliver from the first two items a signal to interference plus noise ratio (SINR) measurement.        
Both UL MU-MIMO/SIMO and DL eigen-beamforming based schedulers rely on the SRS to get the UE's channel estimates and derive the relevant scheduling metric. In particular, for the broadly deployed baseline SIMO UL scheduler, the scheduler makes use of the UE's signal to interference plus noise ratio (SINR) information to compute the scheduling metric and perform link adaptation. The UE's SINR can be directly derived from the first two above metrics or can use additional interference estimates from other reference signals such as the Demodulation Reference Signal (DMRS). The MAC sub-layer uses and potentially accumulates over time the timing offset estimates to issue a Timing Advance (TA) command to the UE, as a MAC control element. Sounding reference signal is also referred to as sounding reference symbol. Within this patent application the term channel quality indicator (CQI) is interchangeable with channel state indicator (CSI), channel state and channel value.